This invention relates to a storage-stable at elevated temperatures, precatalyzed polyepoxide composition which is especially suitable for subsequent reaction with a phenol to produce higher molecular weight fusion products.
The use of precatalyzed polyepoxide compositions and their subsequent reaction with phenols is well-known. See, for example, U.S. Pat. No. 3,477,990, which is directed to precatalyzed polyepoxides containing phosphonium halides as well as their reaction with phenols.
It is also known that the polyepoxide/phenolic reaction can be catalyzed by phosphines as disclosed in U.S. Pat. No. 3,547,881 and by potassium iodide as disclosed in U.S. Pat. No. 3,978,027.
While these known catalysts are quite acceptable as catalysts for the epoxy-phenoxy reaction, when these catalysts are admixed with the epoxy resins to produce a "pre-catalyzed" epoxy composition, the storage stability at elevated temperatures is not acceptable for many applications because of the reduced activity. It has now been found that the elevated temperature storage stability of the precatalyzed epoxy compositions of U.S. Pat. No. 3,477,990 can be significantly improved by the addition of a small amount of a halide or hydroxide of an alkali metal, e.g., potassium iodide or potassium hydroxide.